Simple Dry Boxes for 3D Printing Filament
There are several dry boxes out there for filament, but at the time of this writing the best deals I’m seeing are $60 a box… which seems too expensive.
I was able to put together this simple storage system that is working well for me and I only spend about $8.50 per box ($5/container + $2.83/desiccant + $0.70/cloth). To get started it might cost an additional $25 for a scale, measuring cup, rubber bands, and/or funnel, but if you have those then your are all set.
For each box I use:
- Containers: https://amzn.to/2KyvnTH
- Desiccant: https://amzn.to/3mTZGBy
- Cheesecloth: https://amzn.to/3pkrQqQ
A more expensive alternative is Desiccant Containers, but they will need to be dried more often: https://amzn.to/3ruKsX4
Optional (but awesome) Humidity Sensor so you know when you need to reactivate:
One-time/if you need items…
- Rubber Bands: https://amzn.to/37MNYnW
- Scale: https://amzn.to/37Kt9JK
- Measuring cup: https://amzn.to/34LuEpg (or print one)
- Funnel: https://amzn.to/3mMOBlr (or print one)

I also setup a wireless hygrometer so I know when I need to recharge the silica and that was an additional $46 one time cost, but you don’t need that or can find a cheaper one.
Drying times of old filament
With this method I was able to dry old PETG and here is the graph:

I saw a great improvement in the quality of my prints: stringing was completely eliminated and it was hard to see the lines in the prints with FLEX, PETG, and PLA (at around 15mm layer heights) as soon as the graph flat lined:

The fit
I wish that I could feed the filament out of these boxes, but they turned out to be just too small. They might have worked perfect, but the handle is just small enough to create friction with 70mm spools, but they do fit well for storage:

The Prusament spools are ~70mm from side to side, as long as your filament spools are at this width or smaller than this you should be good to use this method:

For each set…
Here are the containers I use and this has 6 containers ($30/6 = $5 per box):
Then I measure 1/6th the weight of the 2lbs of desiccant and put that into a 1ft x 1ft (30 cm x 30 cm) square of the cheesecloth (I generally double layer the cloth). Here are the reusable desiccant beads, this is enough for 6 boxes (I’m sure you could make this go even further, $17/6 = $2.83 per box):
An alternative to the silica beads + muslin cheesecloth are these desiccant canisters (which might be easier for recharging but are much more expensive $26/4 = $6.50 per box and this is only 40g of desiccant whereas I use 150g so I don’t have to recharge that often): https://amzn.to/3ruKsX4
Here is an example of the cheesecloth (any muslin cloth will work) and this will work for 22 boxes if double layered ($14/22 = $0.70 per box):
To make it…
Put the measuring cup on the scale, put a double layered 1ft x 1ft square of the muslin into the measuring cup and fill the muslin cloth with ~150g of desiccant (2lbs is supposed to be ~904g/6 contaienrs = ~151g/container, but I’ve found they are sometimes a little short on the 2lbs).
This video might help to see how they are made as well:
Optional, but awesome…
A wireless humidity monitor is optional, but it will let you know if the desiccant has stopped working.. something like this Govee hygrometer has worked great for me:
One-time purchases, if needed…
A cheap scale that works great is this Ozeri (was for ~$15):
A measuring cup like this would work fine (or just print one):
A funnel like this one should do the job (or just print one):
Also if you need them, get some rubber bands:
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